AITA for following a woman around Walmart without her consent?

Context needed. I was a stay-at-home-mom with four children. My husband was military and I went to the local Walmart to get groceries and things needed for the house. Now three of my children are (at this time ages 8,5,3 and my only daughter was just a few months old) and two of my boys are on the autism spectrum. Apparently my one boy who isn't on the spectrum, the 5 year old, was having a bad day. While we were in the store, he started acting up, but wanted a toy. I said no because his behavior was inappropriate for receiving a toy. He began to cry/scream. Now my boys are very loud to begin with, and this time was no exception. This set off my oldest, and more severe on the spectrum, son and he began to have a mini meltdown. I chose to purchase the few items I had in my cart and leave until my children calmed down. Of course people are looking at me and I am embarrassed and fed-up because I just needed to get groceries for the week, and of course I have my spawn acting a fool.

I was leaving the checkout and digging in my daughter's diaper bag for my car keys and that was when it happened. We will just call her Karen. Karen comes up to me, to my ear, and says, "Can you shut your kids up?"

Well I am taken aback at this woman's statement. I said that I was just leaving. She then said, "I'm so tired of hearing spoiled kids scream."

Excuse me, they are crying because they aren't spoiled, I had said no.

A devilish smile crossed my face, and my petty came out, so I turned around and followed this woman around the entire store, with my screaming children in tow. Everywhere she went, I went. She yelled at me and told me to leave her alone, but I smiled and spoke over my crying children, "Oh, I was leaving, but YOU reminded me that I needed to pick up a few more things."

*Edit* Let me clarify that my middle son, who is not autistic, is the one who was having the bad day. Normally my kids were generally well-behaved, as I had my two youngest in one cart that I pushed and my groceries were in the cart behind me that I was pulling. My two oldest were holding the sides of the cart ahead of me so that I could keep an eye on them so they couldn't get lost. This is a habit that they still have, holding the cart. My oldest was screaming, but mostly at his brother to be quiet and that he wasn't going to get the toy now. He would get stuck in statements or questions and repeat them incessantly. I was originally going to go out to the car and let the middle boy calm down, but Karen stepped in instead. While she went around the store, I simply picked up more groceries that I needed anyway. She just happened to be going to areas I needed. It was only a matter of maybe 10 minutes that I followed her before I left.

Also, this happened about 18 years ago, my daughter is 18 and a half and my oldest son said he didn't even remember it, so I told my children the story. I watch Charlotte's awesome petty videos and decided to share this with the internet.